Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycoproteins immobilized on membranes can be detected with high selectivity and sensitivity by the four-step procedure described in this work. The glycoproteins are first oxidized by sodium periodate and then polyacrylic polyhydrazides are coupled to the aldehyde groups generated in the sugar part of the glycoproteins. In the third step, a glycoenzyme, such as horseradish peroxidase, is coupled to the remaining hydrazide groups on the polymer through the aldehydes formed in its glycan chains. In the last step, the visualization of glycoproteins is achieved through the reaction product of the bound glycoenzyme. The sensitivity of the glycoprotein detection is most critically dependent on the hydrazide reagent. Thus, dihydrazides were not satisfactory, a trihydrazide was better, and polyhydrazides were the best. Two different polyhydrazides were used. One was based on acrylamide and the other on N-acryloyl-tris(hydroxymethyl)aminomethane. The second one proved to be superior because it gave higher sensitivity with no detectable background staining. We have also investigated the influence of various reaction conditions on staining of glycoproteins having oligomannose and N-acetyllactosamine type glycan chains. Some of them, invertase and fetuin, could be detected with sensitivity similar to that of silver staining in gels and colloidal gold staining on the membranes. The detection of small quantities of Endo H-deglycosylated glycoproteins was possible under standard conditions only if several N-acetylglucosamine residues remained bound to the protein.
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PMID:Polyacrylic polyhydrazides as reagents for detection of glycoproteins. 247 93

Each of the three high-mannose type glycoproteins studied, acid phosphatase, invertase, and glucose oxidase, could be specifically cross-linked through its carbohydrate chains. The procedure involves periodate oxidation of carbohydrate residues followed by reaction of the generated aldehyde groups with adipic acid dihydrazide as a cross-linker. The amount and size as well as solubility of the formed polymers could be efficiently controlled by varying the reaction conditions, i.e., the oxidation degree and the concentrations of glycoproteins, cross-linker, and hydrogen ions during the cross-linking reaction. It was found that the quantity and size of polymers increased with oxidation degree and protein concentration and by lowering the pH. When the protein concentration was above and pH below certain values, depending on the glycoenzyme, insoluble polymers formed. The soluble cross-linked polymers retained a high level of original activity, and the minor decrease in specific activity noticed was shown to occur during the periodate oxidation step. The cross-linked glycoenzymes are much more resistant to denaturation by high temperature and by changes in pH, demonstrating the usefulness of this method in preparation of the stabilized glycoprotein derivatives.
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PMID:Preparation of the stabilized glycoenzymes by cross-linking their carbohydrate chains. 284 Aug 55

Studies with experimental animals indicate that acetaldehyde, the first metabolite of ethanol that is microbially formed in the colonic lumen, may play a role in ethanol-associated colorectal co-carcinogenesis. Although intracoIonic acetaldehyde concentrations are highest during the metabolism of exogenous ethanol, some individuals may also possess marked amounts of endogenous acetaldehyde. Since no information is available concerning the possible effects of acetaldehyde on human colonic epithelial cells, this study was aimed to assess whether this compound, either alone or in combination with ethanol, affects such properties of human neoplastic colonocytes that are considered relevant with regard to cancer development. Human colon adenocarcinoma cell line Caco-2 was used as a model of transformed colonocytes, and effects of acetaldehyde and/or ethanol on the proliferation and differentiation of these cells as well as on their adhesion to collagens I and IV, the most important extracellular matrix proteins in the colon, were studied. The results of this study show that acetaldehyde markedly affects the phenotype of Caco-2 cells without having direct cytotoxic effects. Like many carcinogens, it was found to have a dual effect on cell proliferation rate, acute exposure being inhibitory and chronic exposure stimulating. Acetaldehyde also considerably decreased both sucrase activity and nuclear content of protein kinase A catalytic subunit in Caco-2 cells, which indicate that the differentiation of the cells was disturbed. Moreover, the adhesion of Caco-2 cells to collagens I and IV was dose-dependently reduced by acetaldehyde treatment. All these changes, i.e. enhanced cell proliferation rate (by chronic treatment), decreased differentiation, and reduced adhesion to extracellular matrix proteins, would in vivo predict more aggressive and invasive tumour behaviour. The possibility that colonic intraluminal acetaldehyde, either ethanol-derived or endogenous, might enhance the development of colorectal tumours should therefore be considered.
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PMID:Acetaldehyde alters proliferation, differentiation and adhesion properties of human colon adenocarcinoma cell line Caco-2. 985 20

Invertase from S. cerevisiae has been immobilized on porous silica matrix, formed using sol-gel chemistry, with surface area of approximately 650 m(2)/g. The co-condensation of silica sol with 3-aminopropyl(triethoxy)silane produced an amino-chemically surface modified silica gel (N-CSMG) with a very high ligand loading of 3.6 mmol/g SiO(2); significantly higher than commercially available matrices. Surface amine groups were activated with glutaraldehyde to produce GA-N-CSMG, and invertase covalently attached by the aldehyde. Invertase was used as a model enzyme to measure the immobilizing character of the GA-N-CSMG material. Using an optimized immobilization protocol, a very high loading of 723 mg invertase per gram GA-N-CSMG is obtained; 3-200-fold higher than values published in literature. The reproducible, immobilized activity of 246,000 U/g GA-N-CSMG is also greater than any other in literature. Immobilized invertase showed almost 99% retention of free enzyme activity and no loss in catalytic efficiency. The apparent kinetic parameters K(M) and V(M) were determined using the Michealis-Menten kinetic model. K(M) of the free invertase was 1.5 times greater than that of the immobilized invertase--indicating a higher substrate affinity of the immobilized invertase. These findings show considerable promise for this material as an immobilization matrix in industrial processes.
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PMID:Chemically surface modified gel (CSMG): an excellent enzyme-immobilization matrix for industrial processes. 1664 49

After periodate oxidation of its glycosidic component, invertase was covalently bound onto three types of modified solid supports: glycidyl methacrylate, styrene-divinylbenzene copolymers, and bead cellulose. Direct reaction of the invertase aldehyde groups that were formed with amino groups of the support and use of the modified Ugi reaction have been employed as immobilization procedures. Apart from binding methods, the important effects of the buffer, support, conditions of periodate oxidation, and the length of the spacer on the activity of the enzyme conjugate have been investigated. Superior conjugate activity was obtained, via modified Ugi reaction, by the immobilization of a suitably oxidized invertase to a styrene-divinylbenzene copolymer having free amino groups.
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PMID:Invertase immobilization via its carbohydrate moiety. 1855 40